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  • Author or Editor: Johannes Schramm x
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Bernhard Meyer, Horst Urbach, Carlo Schaller and Johannes Schramm

Object. The authors' goal in this study was to challenge the proposed mechanism of the occlusive hyperemia theory, in which it is asserted that stagnating flow in the former feeding arteries of cerebral arteriovenous malformations (AVMs) leads to parenchymal hypoperfusion or ischemia, from which postoperative edema and hemorrhage originate.

Methods. Cortical oxygen saturation (SaO2) was measured in 52 patients by using microspectrophotometry in areas adjacent to AVMs before and after resection. The appearance of the former feeding arteries was categorized as normal (Group A); moderately stagnating (Group B); and excessively stagnating (Group C) on postoperative angiographic fast-film series. Patients and SaO2 values were pooled accordingly and compared using analysis of variance and Duncan tests (p < 0.05). Angiographic stagnation times in former feeding arteries were correlated in a linear regression/correlation analysis with SaO2 data (p < 0.05). All values are given as the mean ± standard deviation.

The average median postoperative SaO2 in Group C (15 patients) was significantly higher than in Groups B (17 patients) and A (20 patients) (Group C, 75.2 ± 8.5; Group B, 67.5 ± 10.8; Group A, 67.1 ± 12 %SaO2), as was the average postoperative increase in SaO2 (Group C, 25.9 ± 14.9; Group B, 14.6 ± 14; Group A, 11.1 ± 14 %SaO2). Angiographically confirmed stagnation times were also significantly longer in Group C than in Group B (Group C, 5.6 ± 2.5; Group B, 1.3 ± 0.6 seconds). A significant correlation/regression analysis showed a clear trend toward higher postoperative SaO2 levels with increasing stagnation time.

Conclusions. Stagnating flow in former feeding arteries does not cause cortical ischemia, but its presence on angiographic studies is usually indicative of hyperperfusion in the surrounding brain tissue after AVM resection. In the context of the pathophysiology of AVMs extrapolations made from angiographically visible shunt flow to blood flow in the surrounding brain tissue must be regarded with caution.

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Bernhard Meyer, Armin P. Stangl and Johannes Schramm

✓ In this article the authors report the case of a mixed cerebrovascular malformation in which a true arteriovenous malformation (AVM), harboring a nidus, is associated with a venous malformation that serves as the draining vein for the nidus. Despite the authors' preoperative rationale for exclusive extirpation of the AVM, an inadvertent injury and the obliteration of the venous malformation generated delayed postoperative neurological deterioration, which could clearly be attributed to venous hemorrhagic infarction. Because this is only the second instance of this type of mixed vascular malformation of the brain reported, which also underscores the concept of nonsurgical treatment of venous malformations, the authors discuss the diverse literature regarding mixed vascular malformations and the treatment of venous malformations.

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Josef Zentner, Bernhard Meyer, Armin Stangl and Johannes Schramm

✓ Intrinsic insular tumors are frequently excluded from surgical treatment. The authors propose a more extensive approach to these lesions based on the results of this prospective series. From September 1993 to January 1995, 30 patients (18 males and 12 females; mean age 42 years) harboring benign (15 patients) or malignant (15 patients) tumors involving the insula underwent surgical treatment. The dominant and nondominant hemispheres were both affected in 15 cases. Two groups were defined on the basis of preoperative magnetic resonance (MR) imaging: 14 lesions were restricted to the insula and the corresponding opercula; the other 16 lesions also involved other mesocortical and/or allocortical areas. Most patients displayed only mild preoperative symptoms. The median score according to the Karnofsky performance scale was 90. Microsurgical removal was achieved via a transsylvian approach in nine cases and via a frontal and/or temporal approach in 21 cases. According to early postoperative MR imaging, complete tumor removal (100%) was seen in five patients, nearly complete (> 80%) in 21, and incomplete resection (50%–80%) in four patients. There was no operative mortality; 19 patients (63%) experienced immediate postoperative morbidity, including reduced performance. After a mean follow-up review of 8.5 months two of 21 patients suffered permanent deficits, accounting for an overall operative morbidity of 10%. At the mean time of review, three patients with Grade IV tumors had died of tumor recurrence. The authors conclude that low-grade intrinsic insular tumors, as well as Grade III tumors, can be removed with favorable results in the majority of patients. Surgery to excise glioblastomas should only be considered for patients with good preoperative performance and young age.

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Matthias Simon, Georg Neuloh, Marec von Lehe, Bernhard Meyer and Johannes Schramm

Object

Treatment for insular (paralimbic) gliomas is controversial. In this report the authors summarize their experience with microsurgical resection of insular tumors.

Methods

The authors analyzed complications, functional outcomes, and survival in a series of 101 operations performed in 94 patients between 1995 and 2005.

Results

A > 90% resection was achieved in 42%, and 70–90% tumor removal was accomplished in 51% of cases. Functional outcomes varied considerably between patient subgroups. For example, in neurologically intact patients ≤ 40 years of age with WHO Grade I–III tumors, good outcomes (Karnofsky Performance Scale Score 80–100) were seen in 91% of cases. Predictors of an unfavorable functional outcome included histological features of glioblastoma, advanced age, and a low preoperative Karnofsky Performance Scale score. One year after surgery, 76% of patients who had presented with epilepsy were seizure free or experienced only isolated, nondebilitating seizures. Surprisingly good survival rates were seen after surgery for anaplastic gliomas. The median survival for patients with anaplastic astrocytomas (WHO Grade III) was 5 years, and the 5-year survival rate for those with anaplastic oligodendroglial tumors was 80%. Independent predictors of survival included younger age, favorable histological features (WHO Grade I and oligodendroglial tumors), Yaşargil Type 5A/B tumors with frontal extensions, and more extensive resections.

Conclusions

Insular tumor surgery carries substantial complication rates. However, surprisingly similar figures have been reported in large unselected craniotomy series and also after alternative treatment regimens. In view of the oncological benefits of resective surgery, our data would therefore argue for microsurgery as the primary treatment for most patients with a presumed WHO Grade I–III tumor. Patients with glioblastomas and/or age > 60 years require a more cautious approach.

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Rudolf A. Kristof, Ales F. Aliashkevich, Michael Schuster, Bernhard Meyer, Horst Urbach and Johannes Schramm

Object. The authors conducted a study to determine the results of decompressive surgery without fusion in selected patients who presented with radicular compression syndromes caused by degenerative lumbar spondylolisthesis and in whom there was no evidence of hypermobility on flexion—extension radiographs.

Methods. The medical records and radiographs obtained in 49 patients were reviewed retrospectively. Clinical status was quantified by summing self-assessed Prolo Scale scores. All 49 patients (55% female, mean age 68.7 years) presented with leg pain accompanied by lumbalgia in 85.7% of the cases. Preoperatively the median sum of Prolo Scale scores was 4. The mean preoperative degree of forward vertebral displacement was 13.5% and was located at L-4 in 67% of the cases. Osseous decompression alone was performed in 53%, and an additional discectomy at the level of displacement was undertaken in the remaining patients because of herniated discs. Major complications (deep wound infection) occurred in 2%. During a mean follow-up period of 3.73 years, 10.2% of the patients underwent instrumentation-assisted lumbar fusion when decompression alone failed to resolve symptoms. At last follow up the median overall Prolo Scale score was 8. Excellent and good results were demonstrated in 73.5% of the patients. Prolonged back pain (r = 0.381) as well as the preoperative degree of displacement (r = 0.81) and disc space height (r = 0.424) influenced outcome (p ≤ 0.05); additional discectomy for simultaneous disc herniation at the displaced level did not influence outcome (p > 0.05).

Conclusions. These results appear to support a less invasive approach in this subgroup of elderly patients with degenerative lumbar spondylolisthesis—induced radicular compression syndromes and without radiographically documented hypermobility. Additional discectomy for simultaneous disc herniation of the spondylolisthetic level did not adversely influence the outcome. Complication rates are minimized and fusion can eventually be performed should decompression alone fail. A prospective controlled study is required to confirm these results.

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